With lfe version 2.8-5.1 get_fe() produces constant SEs over all covariates in the one-way case. However, they differ per covariate in the two-way case (as expected).
> library(lfe)
> data("Grunfeld", package = "plm")
> mod_felm <- felm(inv ~ value + capital | firm, data = Grunfeld)
> # summary(mod_felm)
>
> fe_lfe <- getfe(mod_felm, se = TRUE, bN = 50)
> print(fe_lfe)
effect obs comp fe idx se
firm.1 -70.296717 20 1 firm 1 11.79928
firm.2 101.905814 20 1 firm 2 11.79928
firm.3 -235.571841 20 1 firm 3 11.79928
firm.4 -27.809295 20 1 firm 4 11.79928
firm.5 -114.616813 20 1 firm 5 11.79928
firm.6 -23.161295 20 1 firm 6 11.79928
firm.7 -66.553474 20 1 firm 7 11.79928
firm.8 -57.545657 20 1 firm 8 11.79928
firm.9 -87.222272 20 1 firm 9 11.79928
firm.10 -6.567844 20 1 firm 10 11.79928
With lfe version 2.8-5.1
get_fe()produces constant SEs over all covariates in the one-way case. However, they differ per covariate in the two-way case (as expected).